Mixed esters of dibasic unsaturated acids, glycols and glycidyl esters

ABSTRACT

Mixed esters of dibasic unsaturated acids, glycols and glycidyl esters, when formulated with aminoplast resins, form coating compositions which require little or no organic liquid carrier. These compositions are useful for finishing appliances and automobiles and for general industrial use.

United States Patent F ng [451 Dec. 23, 1975 MIXED ESTERS 0F DIBASIC 3,414,635 12/1968 Edwards et a1. 260/485 0 3,433,824 3/1969 Horsley 260/485 0 UNSATURATED ACIDS, GLYCOLS AND GLYCIDYL ESTERS Inventor: James C. Fang, Media, Pa.

Assignee: E. I. Du Pont de Nemours & Co.,

Wilmington, Del.

Filed: Mar. 5, 1973 Appl. No.2 338,053

US. CL... 260/485 G; 117/132 R; 117/132 BF; 117/148; 117/161 LN; 117/161 UN; 117/161 UA; 260/31.4 R; 260/31.6; 260/404.8

Int. Cl. C07C 69/52; C07C 69/60 Field of Search 260/485 G, 404.8

References Cited UNITED STATES PATENTS 2/1967 McGary et al. 260/475 P FOREIGN PATENTS OR APPLICATIONS 942,465 ll/l963 United Kingdom 260/485 G Primary Examiner'James A. Patten Assistant Examiner-E. Jane Skelly ABSTRACT 8 Claims, No Drawings MIXED ESTERS OF DIBASIC UNSATURATED ACIDS, GLYCOLS AND GLYCIDYL ESTERS BACKGROUND OF THE INVENTION There has been much emphasis in recent years on developing coating compositions which do not pollute the atmosphere as they dry. This has become increasingly important with the passage of legislation strictly limiting the amounts and kinds of organic liquids than can be emitted during industrial finishing operations.

The esters of my invention, when formulated with aminoplast resins, form coating compositions which require little or no organic liquid carrier to bring them to application viscosity. My compositions emit a minimum of volatiles into the air as they cure.

Their low liquid content also carries with it additional benefits. Since my compositions have an extremely high film-forming solids content, the saving in shipping costs is considerable. Their high solids content also makes it possible, in spray applications, to apply more of the composition per pass of the spray gun, thereby saving much in labor costs.

My compositions also have the advantage of being compatible with most conventional mill bases used in the paint industry to pigment coating compositions.

In addition, when cured by conventional baking techniques, my compositions give hard, durable, glossy, flexible finishes with excellent adhesion to unprimed metal.

All these properties suit my compositions for use in finishing appliances, metal furniture, wood and plasties, for coil coating operations and for topcoating automobiles.

SUMMARY OF THE INVENTION The esters of my invention are the mixed esters of unsaturated dibasic acids with glycols and with glycidyl esters. More particularly, my esters are those represented by the structural formula where X is hydrogen, an'alkyl radical of 1-4 carbon atoms or phenyl; Y is hydrogen, OH, -CH OI-I or an alkyl radical of 1-4 carbon atoms (only one Y can be OH);

D is hydrogen or C H Ol-l; D is hydrogen or -OH; (but one of D or D must be OH or CH OH) R is an alkyl radical of 4l8 carbon atoms, or a singly, doubly or triply unsaturated hydrocarbon radical of 17 carbon atoms;

n is 0 or I;

p is-O or 1; and

t is O or 1.

The mixed esters I prefer are those represented by formula (1) where I. a. X is hydrogen, n is O, m is l and Y is hydrogen; b. X is hydrogen, n is O, m is l and Y is CH;, and

hydrogen; or c. X is hydrogen, n is O, m is 2 and Y is (l) hydrogen and OH and (2) hydrogen and hydrogen; and t II. D, is hydrogen, D is OH, 12 is l, O is tislandRis' Preparation of The Esters I first react about 1 mol of a suitable dibasic unsaturated acid with about 1 mol of a suitable polyol according to the illustrative equation fumaric acid propylene glycol HZI I catalyze this reaction with about 0.25%, by weight, of

3 4 I then react about 1 mol of the resulting intermediate It will be apparent from the foregoing equations that with 0.4 to 1.0 mol of a glycidyl ester, a glycidyl ether small amounts of isomers of the product shown will be or an alkylene oxide, according to the illustrative equaformed. For example, when maleic acid is used, the tion product will partially isomerize to the trans form (fu- CH;, (l) O O maric acid). [Where R2 and R3 are as m formula Also, the hydroxyl group or Ch OH [D in formula I m rx the reactants and then heat the mixture to (1)] which results from rupturing the cyclic ether ring 180 2O0 under mtrogen and 9 It at that of a glycidyl compound may be attached in either of the perature for about 1 hour. Preparation of my ester is positions Shown then complete. In addition, the intermediate, for the most part, The dibasrc unsaturated acids I use in this process are Opens the Cyclic ether ring by reaction with the cap fumanc, maleic and itacomc. Maleic anhydride can boxyl group, as shown in equation (3). However some also be f rupturing is brought about by reaction with the hyulustranve of poly 01s can be used j ethylene droxyl group on the intermediate. This isomeric form is glycol lz'propanedlolz not represented by formula (1) because such small blltanedlol ls'pemanedlol glycerol quantities are produced, but I nevertheless consider it triol, l,2,3,4-butanetetrol, l,6-hexanediol, neopentyl to be a part of my invention glycol, diethylene glycol, trimethylolpropane and Similarly the alkyl groups of X and Y in formula 1 trimethylpentfmediol I prefer to use ethylene glycol can vary in position according to which hydroxyl group e of an unsymmetrical glycol is attacked by the acid Illustrative of the glycidyl compounds WI'llCh can be when the two are reacted as shown in equation used are esters of glycidol monobflsic acids, of These isomeric forms can be isolated from the main 448 carbon atoms Such as glycldyl palm'tate glyc'dyl product by chromatographic techniques, if this is delaurate and glycidyl Stearate; alkylene Oxides of 4-18 sired. But I have found that isolation is unnecessary carbon atoms Such as .butylene Oxlde; and glyc'dyl because all of the isomers are useful for the purposes I ethers Such.as octyl glycidyl ether have already described. Indeed, the presence of these when. R m formula (I) an unsatufated hydmcar' isomeric forms in some cases makes the compositions radlcal I use as the reactant a glyc'dyl ester repre' compatible with a wider variety of film-formers and sented by the Structure 40 lowers their viscosity. I therefore prefer and recommend that the various isomers not be isolated.

In preparing my esters, one may use mixtures of Q acids, of glycols and of glycidyl compounds if he wishes to obtain a balance of properties. Suitable mixtures and o the amounts in which the components of these mixtures are to be used will be immediately apparent to anyone where R is a singly, doubly or triply unsaturated hyversed in the polymer or paint art.

drocarbon radical of 17 carbon atoms. This ester can be prepared by the reaction of a suitable How My Mlxed Esters Are Used soap with epichlorohydrin. When the soap is derived I mix the product of the foregoing preparation from a naturally occurring oil such as linseed oil, soya scheme with a conventional aminoplast resin such as a oil, safflower oil, tall oil, or chinawood oil, the glycidyl melamine-formaldehyde resin, a benzoguanamine-forester, and the final product it gives, is a mixture of maldehyde resin, a urea-formaldehyde resin, a melacompounds whose R groups vary from each other, the mine toluene-sulfonamide resin, a hexamethoxymevariance of course depending on the nature of the oil. thylmelamine resin, or any of the alkylated melamine- I especially prefer to use a mixed glycidyl ester formaldehyde, benzoguanamine-formaldehyde or ureaknown as Cardura E ester which is represented by formaldehyde resins. I prefer to use a hexamethoxymethe structure thylmelamine resin.

I prepare this mixture so that it contains approximately 50-80%, by weight of the total, of my ester and o R. C H CH 0 ll L R approximately 20% to about 50%, by weight of the 2 total, of the aminoplast resin.

0 R3 After the components have been thoroughly mixed, I

add a pigment, if this is desired, by way of a convenwhere R1 is and R2 and R3 are lower alkyl, the tional mill base. This mill-base can be based, for examtotal numhgr of Carbon atoms in Rh R2 and R3 ple on an alkyd resm oralow molecular weight acrylic being 1' resin. The amount of mill base used is conventional and 1. Sold by Shell Chemical Company will depend on the depth of color desired. Generally speaking no compatibility problems will be encountered for my coating compositions arecompatible with most mill bases conventionally used in the industry. Preparation of the coating composition is then complete.

All that is required to reduce my coating compositions to spray application viscosity is to heat them to approximately 4055C. The compositions can also be reduced to spray viscosity by the addition of such conventional thinners as toluene, methylethyl ketone or acetone. In general, this causes no problems for my compositions are also compatible with most such organic liquids. However, I find this dilution to be unnecessary, for it only introduces organic liquids into my compositions which the law now requires to be at low concentration or completely absent, and whose presence confers no advantages.

However my compositions are thinned, they are ordinarily sprayed to whatever substrate is being coated, although other techniques such as brushing, dipping, rollercoating or doctor-blading can be employed. If spray application is the method of choice, those skilled in the art will be pleased to note that no special spraying equipment or techniques are required. My compositions can be conventionally sprayed with no loss of quality or economy.

The thickness to which my compositions are applied is largely a matter of choice, but, as already mentioned, it is possible in most cases to apply somewhat thicker coats than is the rule with conventional coating compositions without the accompanying sagging and running.

My compositions, however they are applied, are then cured by baking the coated articles for approximately [2 hour at 120l80C. to give hard, glossy, durable, flexible finishes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Those skilled in the polymer and paint art will be able to practice my invention with greater case after having read the following illustrative examples. I recognize that these artisans will be able to compose numerous variations on the examples theme, such as the introduction of substituents, not shown here, onto the basic molecule, and the use of conventional adjuncts. I consider all of these variations to be within my inventive concept.

EXAMPLE 1 The following were mixed together in a reaction kettle:

Parts Fumaric acid 1 16 Propylene glycol 76 Toluenesulfonic acid 0.5 p-methoxyphenol 0.1

This mixture was heated to 135l46C. and held there for 45 minutes to 1 hour, while approximately 18 parts of water were given off.

Cardura E ester, 200 parts, was then added to the reaction mixture over a 2 minute period. The mixture was then held at 180-200C. for approximately 1 hour, while 2-3 parts of an impurity in the form of a distillate were collected. The resulting product was an oily straw-colored liquid, having a Gardner-Ho1dt viscosity of 2-3.

6 Maleic acid and itaconic acid can be used in place of fumaric acid in this process, in equivalent molar amounts, with substantially the same result. Similarly, ethylene glycol or glycerol can be substituted for prop- 5 ylene glycol.

EXAMPLE 2 The following were thoroughly mixed:

Parts Product of Example 1 Hexumcthoxymethylmelamine Mill base Composed of TiO Non-drying oil alkyd resin 60% (solids in toluene Xylene 50/50) Toluene where X is the residue of ethylene glycol, l ,2-propanedio1, 1 ,3-p ropanediol, l ,4-butanedio1, l ,S-pentanediol, glycerol, 1,2,3 -butanetriol, 1 1,2,3 ,4-butanetetro1 1,6-hexanedio1, neopentyl glycol, diethylene glycol, trimethylol propane or trimethylpentanediol;

H HH Z is OH H OH and R is an alkyl radical of 41 8 carbon atoms, or singly, doubly or triply unsaturated hydrocarbon radical of 17 carbon atoms.

7 8 2. The compound of claim 1 wherein X is the residue where R is CH, and R and R are lower alkyl, the of ethylene glycol. total number of carbon atoms in R R and R 3. The compound of claim 1 wherein X is the residue being 7-] l. of l,2-propanediol. 7. The compound of claim 3 wherein D is 4. The compound of claim 1 wherein X is the residue 5 of glycerol. -CH2CH-CH2 5. The compound of claim 1 wherein D is OH CH2-CHCH2- l and R is and R is l--R L. Tr R2 where R, is -CH and R and R are lower alkyl, the RI total number of carbon atoms in R R and R being 7-] l.

where R is CH;; and R and R are lower alkyl, the The Compound of Glam 4 where!" D 15 total number of carbon atoms in R R and R CH CHCH being 71 1. 6. The compound of claim 2 wherein D is ,CH2CH-CH2 and R is l and R is c R '1 where R is CH and R and R are lower alkyl, the total number of carbon atoms in R R and R being 7-11. 

1. A COMPOUND REPRESENTED BY THE STRUCTURE
 2. The compound of claim 1 wherein X is the residue of ethylene glycol.
 3. The compound of claim 1 wherein X is the residue of 1,2-propanediol.
 4. The compound of claim 1 wherein X is the residue of glycerol.
 5. The compound of claim 1 wherein D is
 6. The compound of claim 2 wherein D is
 7. The compound of claim 3 wherein D is
 8. The compound of claim 4 wherein D is 